Summary

In maritime climates the production of winter wheat often leads to high nitrate leaching losses. In this study mixtures of winter wheat and catch crops were analyzed as alternative growing system to avoid high leaching losses. In a field experiment pure winter wheat grown as control showed highest N-losses. Leaching losses of 140 kg N ha-1 after the pre-crop grass-clover and of 50 kg N ha-1 after oats as pre-crop were measured. Compared to this, growing winter wheat in mixture with forage rape or oats reduced nitrate leaching by 50 %. Common vetch as mixture partner to winter wheat had a lower potential to reduce leaching losses. Comparable results were obtained growing the catch crops alone followed by spring wheat. Due to the competition for growth factors between catch crops and cereal, yields of the tested mixtures were lower than those of spring wheat grown after catch crops as well as of the winter wheat control. Early sown mixtures of winter wheat and catch crops showed satisfactory yields.